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Benham PM, Cicero C, Escalona M, Beraut E, Fairbairn C, Marimuthu MPA, Nguyen O, Sahasrabudhe R, King BL, Thomas WK, Kovach AI, Nachman MW, Bowie RCK. Remarkably High Repeat Content in the Genomes of Sparrows: The Importance of Genome Assembly Completeness for Transposable Element Discovery. Genome Biol Evol 2024; 16:evae067. [PMID: 38566597 PMCID: PMC11088854 DOI: 10.1093/gbe/evae067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/01/2024] [Accepted: 03/23/2024] [Indexed: 04/04/2024] Open
Abstract
Transposable elements (TE) play critical roles in shaping genome evolution. Highly repetitive TE sequences are also a major source of assembly gaps making it difficult to fully understand the impact of these elements on host genomes. The increased capacity of long-read sequencing technologies to span highly repetitive regions promises to provide new insights into patterns of TE activity across diverse taxa. Here we report the generation of highly contiguous reference genomes using PacBio long-read and Omni-C technologies for three species of Passerellidae sparrow. We compared these assemblies to three chromosome-level sparrow assemblies and nine other sparrow assemblies generated using a variety of short- and long-read technologies. All long-read based assemblies were longer (range: 1.12 to 1.41 Gb) than short-read assemblies (0.91 to 1.08 Gb) and assembly length was strongly correlated with the amount of repeat content. Repeat content for Bell's sparrow (31.2% of genome) was the highest level ever reported within the order Passeriformes, which comprises over half of avian diversity. The highest levels of repeat content (79.2% to 93.7%) were found on the W chromosome relative to other regions of the genome. Finally, we show that proliferation of different TE classes varied even among species with similar levels of repeat content. These patterns support a dynamic model of TE expansion and contraction even in a clade where TEs were once thought to be fairly depauperate and static. Our work highlights how the resolution of difficult-to-assemble regions of the genome with new sequencing technologies promises to transform our understanding of avian genome evolution.
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Affiliation(s)
- Phred M Benham
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Carla Cicero
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Merly Escalona
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Eric Beraut
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Colin Fairbairn
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA
| | - Mohan P A Marimuthu
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California-Davis, Davis, CA 95616, USA
| | - Oanh Nguyen
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California-Davis, Davis, CA 95616, USA
| | - Ruta Sahasrabudhe
- DNA Technologies and Expression Analysis Core Laboratory, Genome Center, University of California-Davis, Davis, CA 95616, USA
| | - Benjamin L King
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469, USA
| | - W Kelley Thomas
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Adrienne I Kovach
- Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH 03824, USA
| | - Michael W Nachman
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Rauri C K Bowie
- Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, CA 94720, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720, USA
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2
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Clancey E, MacPherson A, Cheek RG, Mouton JC, Sillett TS, Ghalambor CK, Funk WC, Hohenlohe PA. Unraveling Adaptive Evolutionary Divergence at Microgeographic Scales. Am Nat 2024; 203:E35-E49. [PMID: 38306284 DOI: 10.1086/727723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
AbstractStriking examples of local adaptation at fine geographic scales are increasingly being documented in natural populations. However, the relative contributions made by natural selection, phenotype-dependent dispersal (when individuals disperse with respect to a habitat preference), and mate preference in generating and maintaining microgeographic adaptation and divergence are not well studied. Here, we develop quantitative genetics models and individual-based simulations (IBSs) to uncover the evolutionary forces that possibly drive microgeographic divergence. We also perform Bayesian estimation of the parameters in our IBS using empirical data on habitat-specific variation in bill morphology in the island scrub-jay (Aphelocoma insularis) to apply our models to a natural system. We find that natural selection and phenotype-dependent dispersal can generate the patterns of divergence we observe in the island scrub-jay. However, mate preference for a mate with similar bill morphology, even though observed in the species, does not play a significant role in driving divergence. Our modeling approach provides insights into phenotypic evolution occurring over small spatial scales relative to dispersal ranges, suggesting that adaptive divergence at microgeographic scales may be common across a wider range of taxa than previously thought. Our quantitative genetic models help to inform future theoretical and empirical work to determine how selection, habitat preference, and mate preference contribute to local adaptation and microgeographic divergence.
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3
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Carbeck K, Arcese P, Lovette I, Pruett C, Winker K, Walsh J. Candidate genes under selection in song sparrows co-vary with climate and body mass in support of Bergmann's Rule. Nat Commun 2023; 14:6974. [PMID: 37935683 PMCID: PMC10630373 DOI: 10.1038/s41467-023-42786-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023] Open
Abstract
Ecogeographic rules denote spatial patterns in phenotype and environment that may reflect local adaptation as well as a species' capacity to adapt to change. To identify genes underlying Bergmann's Rule, which posits that spatial correlations of body mass and temperature reflect natural selection and local adaptation in endotherms, we compare 79 genomes from nine song sparrow (Melospiza melodia) subspecies that vary ~300% in body mass (17 - 50 g). Comparing large- and smaller-bodied subspecies revealed 9 candidate genes in three genomic regions associated with body mass. Further comparisons to the five smallest subspecies endemic to California revealed eight SNPs within four of the candidate genes (GARNL3, RALGPS1, ANGPTL2, and COL15A1) associated with body mass and varying as predicted by Bergmann's Rule. Our results support the hypothesis that co-variation in environment, body mass and genotype reflect the influence of natural selection on local adaptation and a capacity for contemporary evolution in this diverse species.
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Affiliation(s)
- Katherine Carbeck
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, T6T 1Z4, Canada.
| | - Peter Arcese
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, T6T 1Z4, Canada
| | - Irby Lovette
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, 14850, USA
| | - Christin Pruett
- Department of Biology, Ouachita Baptist University, Arkadelphia, AR, 71998, USA
| | - Kevin Winker
- University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
| | - Jennifer Walsh
- Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
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4
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Recuerda M, Palacios M, Frías O, Hobson K, Nabholz B, Blanco G, Milá B. Adaptive phenotypic and genomic divergence in the common chaffinch (Fringilla coelebs) following niche expansion within a small oceanic island. J Evol Biol 2023; 36:1226-1241. [PMID: 37485603 DOI: 10.1111/jeb.14200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 07/25/2023]
Abstract
According to models of ecological speciation, adaptation to adjacent, contrasting habitat types can lead to population divergence given strong enough environment-driven selection to counteract the homogenizing effect of gene flow. We tested this hypothesis in the common chaffinch (Fringilla coelebs) on the small island of La Palma, Canary Islands, where it occupies two markedly different habitats. Isotopic (δ13 C, δ15 N) analysis of feathers indicated that birds in the two habitats differed in ecosystem and/or diet, and analysis of phenotypic traits revealed significant differences in morphology and plumage colouration that are consistent with ecomorphological and ecogeographical predictions respectively. A genome-wide survey of single-nucleotide polymorphism revealed marked neutral structure that was consistent with geography and isolation by distance, suggesting low dispersal. In contrast, loci putatively under selection identified through genome-wide association and genotype-environment association analyses, revealed amarked adaptive divergence between birds in both habitats. Loci associated with phenotypic and environmental differences among habitats were distributed across the genome, as expected for polygenic traits involved in local adaptation. Our results suggest a strong role for habitat-driven local adaptation in population divergence in the chaffinches of La Palma, a process that appears to be facilitated by a strong reduction in effective dispersal distances despite the birds' high dispersal capacity.
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Affiliation(s)
- María Recuerda
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
| | - Mercè Palacios
- Department of Biodiversity, Ecology and Evolution, Universidad Complutense de Madrid, Madrid, Spain
| | - Oscar Frías
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
| | - Keith Hobson
- Biology Department, Western University, London, Ontario, Canada
| | - Benoit Nabholz
- Institut des Sciences de l'Évolution de Montpellier (ISEM), CNRS, EPHE, IRD, Université de Montpellier, Montpellier, France
- Institut Universitaire de France (IUF), Paris, France
| | - Guillermo Blanco
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
| | - Borja Milá
- National Museum of Natural Sciences, Spanish National Research Council (CSIC), Madrid, Spain
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Zhang L, Chen J, Zhao R, Zhong J, Lin L, Li H, Ji X, Qu Y. Genomic insights into local adaptation in the Asiatic toad Bufo gargarizans, and its genomic offset to climate warming. Evol Appl 2023; 16:1071-1083. [PMID: 37216027 PMCID: PMC10197391 DOI: 10.1111/eva.13555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/31/2023] [Accepted: 04/20/2023] [Indexed: 05/24/2023] Open
Abstract
Genomic signatures of local adaptation have been identified in many species but remain sparsely studied in amphibians. Here, we explored genome-wide divergence within the Asiatic toad, Bufo gargarizans, to study local adaptation and genomic offset (i.e., the mismatch between current and future genotype-environment relationships) under climate warming scenarios. We obtained high-quality SNP data for 94 Asiatic toads from 21 populations in China to study spatial patterns of genomic variation, local adaptation, and genomic offset to warming in this wide-ranging species. Population structure and genetic diversity analysis based on high-quality SNPs revealed three clusters of B. gargarizans in the western, central-eastern, and northeastern portions of the species' range in China. Populations generally dispersed along two migration routes, one from the west to the central-east and one from the central-east to the northeast. Both genetic diversity and pairwise F ST were climatically correlated, and pairwise F ST was also correlated with geographic distance. Spatial genomic patterns in B. gargarizans were determined by the local environment and geographic distance. Global warming will increase the extirpation risk of B. gargarizans.
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Affiliation(s)
- Lu‐Wen Zhang
- College of Life SciencesNanjing Normal UniversityNanjingChina
| | - Jun‐Qiong Chen
- College of Life SciencesNanjing Normal UniversityNanjingChina
| | - Ru‐Meng Zhao
- College of Life SciencesNanjing Normal UniversityNanjingChina
| | - Jun Zhong
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental SciencesWenzhou UniversityWenzhouChina
| | - Long‐Hui Lin
- College of Life and Environmental SciencesHangzhou Normal UniversityHangzhouChina
| | - Hong Li
- College of Life SciencesNanjing Normal UniversityNanjingChina
| | - Xiang Ji
- Zhejiang Provincial Key Laboratory for Water Environment and Marine Biological Resources Protection, College of Life and Environmental SciencesWenzhou UniversityWenzhouChina
| | - Yan‐Fu Qu
- College of Life SciencesNanjing Normal UniversityNanjingChina
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Sethuraman A. Teaching computational genomics and bioinformatics on a high performance computing cluster-a primer. Biol Methods Protoc 2022; 7:bpac032. [PMID: 36561335 PMCID: PMC9767868 DOI: 10.1093/biomethods/bpac032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 10/14/2022] [Accepted: 10/17/2022] [Indexed: 11/16/2022] Open
Abstract
The burgeoning field of genomics as applied to personalized medicine, epidemiology, conservation, agriculture, forensics, drug development, and other fields comes with large computational and bioinformatics costs, which are often inaccessible to student trainees in classroom settings at universities. However, with increased availability of resources such as NSF XSEDE, Google Cloud, Amazon AWS, and other high-performance computing (HPC) clouds and clusters for educational purposes, a growing community of academicians are working on teaching the utility of HPC resources in genomics and big data analyses. Here, I describe the successful implementation of a semester-long (16 week) upper division undergraduate/graduate level course in Computational Genomics and Bioinformatics taught at San Diego State University in Spring 2022. Students were trained in the theory, algorithms and hands-on applications of genomic data quality control, assembly, annotation, multiple sequence alignment, variant calling, phylogenomic analyses, population genomics, genome-wide association studies, and differential gene expression analyses using RNAseq data on their own dedicated 6-CPU NSF XSEDE Jetstream virtual machines. All lesson plans, activities, examinations, tutorials, code, lectures, and notes are publicly available at https://github.com/arunsethuraman/biomi609spring2022.
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Affiliation(s)
- Arun Sethuraman
- Correspondence address. Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA. E-mail:
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7
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Clark JD, Benham PM, Maldonado JE, Luther DA, Lim HC. Maintenance of local adaptation despite gene flow in a coastal songbird. Evolution 2022; 76:1481-1494. [PMID: 35700208 PMCID: PMC9545442 DOI: 10.1111/evo.14538] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 03/09/2022] [Accepted: 03/19/2022] [Indexed: 01/22/2023]
Abstract
Adaptation to local environments is common in widespread species and the basis of ecological speciation. The song sparrow (Melospiza melodia) is a widespread, polytypic passerine that occurs in shrubland habitats throughout North America. We examined the population structure of two parapatric subspecies that inhabit different environments: the Atlantic song sparrow (M. m. atlantica), a coastal specialist, and the eastern song sparrow (M. m. melodia), a shrubland generalist. These populations lacked clear mitochondrial population structure, yet coastal birds formed a distinct nuclear genetic cluster. We found weak overall genomic differentiation between these subspecies, suggesting either recent divergence, extensive gene flow, or a combination thereof. There was a steep genetic cline at the transition to coastal habitats, consistent with isolation by environment, not isolation by distance. A phenotype under divergent selection, bill size, varied with the amount of coastal ancestry in transitional areas, but larger bill size was maintained in coastal habitats regardless of ancestry, further supporting a role for selection in the maintenance of these subspecies. Demographic modeling suggested a divergence history of limited gene flow followed by secondary contact, which has emerged as a common theme in adaptive divergence across taxa.
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Affiliation(s)
- Jonathan D. Clark
- Department of Environmental Science and PolicyGeorge Mason UniversityFairfaxVirginia22030,Current Address: Department of Natural Resources and the EnvironmentUniversity of New HampshireDurhamNew Hampshire03824
| | - Phred M. Benham
- Museum of Vertebrate ZoologyUniversity of California, BerkeleyBerkeleyCalifornia94720
| | - Jesus E. Maldonado
- Department of Environmental Science and PolicyGeorge Mason UniversityFairfaxVirginia22030,Center for Conservation GenomicsSmithsonian Conservation Biology InstituteWashingtonD.C.20013
| | - David A. Luther
- Department of BiologyGeorge Mason UniversityFairfaxVirginia22030
| | - Haw Chuan Lim
- Center for Conservation GenomicsSmithsonian Conservation Biology InstituteWashingtonD.C.20013,Department of BiologyGeorge Mason UniversityFairfaxVirginia22030
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Carbeck K, Wang T, Reid JM, Arcese P. Adaptation to climate change through seasonal migration revealed by climatic versus demographic niche models. GLOBAL CHANGE BIOLOGY 2022; 28:4260-4275. [PMID: 35366358 DOI: 10.1111/gcb.16185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 03/15/2022] [Indexed: 06/14/2023]
Abstract
Predicting the geographic range of species and their response to climatic variation and change are entwined goals in conservation and evolutionary ecology. Species distribution models (SDMs) are foundational in this effort and used to visualize the geographic range of species as the spatial representation of its realized niche. SDMs are also used to forecast range shifts under climate change, but often in the absence of empirical evidence that climate limits population growth. We explored the influence of climate on demography, seasonal migration, and the extent of the geographic range in song sparrows (Melospiza melodia), a species thought to display marked local adaptation to regional climate. To do so, we developed SDMs to predict the demographic and climate niches of migratory and resident song sparrows across our study area in western North America from California to Alaska, using 48 years of demographic data from a focal population in British Columbia and 1.2 million continental-scale citizen science observations. Spatial agreement of our demographic and climate niche models in the region of our focal population was strong (76%), supporting the hypothesis that demographic performance and the occurrence of seasonal migration varied predictably with climatic conditions. In contrast, agreement at the northern (58%) and southern (40%) extents of our study area was lower, as expected if the factors limiting population growth vary regionally. Our results support the hypothesis that local climate drives spatial variation in the occurrence of seasonal migration in song sparrows by limiting the fitness of year-round residents, and suggest that climate warming has favored range expansions and facilitated an upward shift in elevational range song sparrows that forgo seasonal migration. Our work highlights the potential role of seasonal migration in climate adaptation and limits on the reliability of climate niche models not validated with demographic data.
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Affiliation(s)
- Katherine Carbeck
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tongli Wang
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jane M Reid
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
- Centre for Biodiversity Dynamics, Institutt for Biologi, NTNU, Trondheim, Norway
| | - Peter Arcese
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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9
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Davis HR, Des Roches S, Anderson RA, Leaché AD. Population expansion, divergence, and persistence in Western Fence Lizards (Sceloporus occidentalis) at the northern extreme of their distributional range. Sci Rep 2022; 12:6310. [PMID: 35428834 PMCID: PMC9012774 DOI: 10.1038/s41598-022-10233-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 03/28/2022] [Indexed: 11/09/2022] Open
Abstract
Population dynamics within species at the edge of their distributional range, including the formation of genetic structure during range expansion, are difficult to study when they have had limited time to evolve. Western Fence Lizards (Sceloporus occidentalis) have a patchy distribution at the northern edge of their range around the Puget Sound, Washington, where they almost exclusively occur on imperiled coastal habitats. The entire region was covered by Pleistocene glaciation as recently as 16,000 years ago, suggesting that populations must have colonized these habitats relatively recently. We tested for population differentiation across this landscape using genome-wide SNPs and morphological data. A time-calibrated species tree supports the hypothesis of a post-glacial establishment and subsequent population expansion into the region. Despite a strong signal for fine-scale population genetic structure across the Puget Sound with as many as 8-10 distinct subpopulations supported by the SNP data, there is minimal evidence for morphological differentiation at this same spatiotemporal scale. Historical demographic analyses suggest that populations expanded and diverged across the region as the Cordilleran Ice Sheet receded. Population isolation, lack of dispersal corridors, and strict habitat requirements are the key drivers of population divergence in this system. These same factors may prove detrimental to the future persistence of populations as they cope with increasing shoreline development associated with urbanization.
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Affiliation(s)
- Hayden R Davis
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, 98195, USA.
| | - Simone Des Roches
- School of Aquatic and Fisheries Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Roger A Anderson
- Department of Biology, Western Washington University, Bellingham, WA, 98225, USA
| | - Adam D Leaché
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, 98195, USA
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10
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Cheek RG, Forester BR, Salerno PE, Trumbo DR, Chen N, Sillett TS, Morrison SA, Ghalambor CK, Funk WC. Habitat-linked genetic variation supports microgeographic adaptive divergence in an island-endemic bird species. Mol Ecol 2022; 31:2830-2846. [PMID: 35315161 PMCID: PMC9325526 DOI: 10.1111/mec.16438] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/03/2022] [Accepted: 03/14/2022] [Indexed: 11/27/2022]
Abstract
We investigated the potential mechanisms driving habitat-linked genetic divergence within a bird species endemic to a single 250 km2 island. The island scrub-jay (Aphelocoma insularis) exhibits microgeographic divergence in bill morphology across pine-oak ecotones on Santa Cruz Island, California (USA) similar to adaptive differences described in mainland congeners over much larger geographic scales. To test whether individuals exhibit genetic differentiation related to habitat type and divergence in bill length, we genotyped over 3,000 single nucleotide polymorphisms (SNPs) in 123 adult island scrub-jay males from across Santa Cruz Island using restriction site-associated DNA sequencing (RADseq). Neutral landscape genomic analyses revealed that genome-wide genetic differentiation was primarily related to geographic distance and differences in habitat composition. We also found 168 putatively adaptive loci associated with habitat type using multivariate redundancy analysis (RDA) while controlling for spatial effects. Finally, two genome-wide association analyses revealed a polygenic basis to variation in bill length with multiple loci detected in or near genes known to affect bill morphology in other birds. Our findings support the hypothesis that divergent selection at microgeographic scales can cause adaptive divergence in the presence of ongoing gene flow.
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Affiliation(s)
- Rebecca G Cheek
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Brenna R Forester
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Patricia E Salerno
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.,Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb), Facultad de Ciencias de Medio Ambiente, Universidad Tecnológica Indoamérica, Quito, Ecuador
| | - Daryl R Trumbo
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA
| | - Nancy Chen
- Department of Biology, University of Rochester, Rochester, NY, 14627, USA
| | - T Scott Sillett
- Migratory Bird Center, Smithsonian's National Zoo and Conservation Biology Institute, Washington, DC, 20013, USA
| | | | - Cameron K Ghalambor
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523, USA.,Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), N-7491, Trondheim, Norway
| | - W Chris Funk
- Department of Biology, Colorado State University, Fort Collins, Colorado, 80523, USA.,Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, 80523, USA
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11
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Gamboa MP, Ghalambor CK, Scott Sillett T, Morrison SA, Chris Funk W. Adaptive divergence in bill morphology and other thermoregulatory traits is facilitated by restricted gene flow in song sparrows on the California Channel Islands. Mol Ecol 2021; 31:603-619. [PMID: 34704295 DOI: 10.1111/mec.16253] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/20/2021] [Accepted: 09/27/2021] [Indexed: 02/06/2023]
Abstract
Disentangling the effects of neutral and adaptive processes in maintaining phenotypic variation across environmental gradients is challenging in natural populations. Song sparrows (Melospiza melodia) on the California Channel Islands occupy a pronounced east-west climate gradient within a small spatial scale, providing a unique opportunity to examine the interaction of genetic isolation (reduced gene flow) and the environment (selection) in driving variation. We used reduced representation genomic libraries to infer the role of neutral processes (drift and restricted gene flow) and divergent selection in driving variation in thermoregulatory traits with an emphasis on the mechanisms that maintain bill divergence among islands. Analyses of 22,029 neutral SNPs confirm distinct population structure by island with restricted gene flow and relatively large effective population sizes, suggesting bill differences are probably not a product of genetic drift. Instead, we found strong support for local adaptation using 3294 SNPs in differentiation-based and environmental association analyses coupled with genome-wide association tests. Specifically, we identified several putatively adaptive and candidate loci in or near genes involved in bill development pathways (e.g., BMP, CaM, Wnt), confirming the highly complex and polygenic architecture underlying bill morphology. Furthermore, we found divergence in genes associated with other thermoregulatory traits (i.e., feather structure, plumage colour, and physiology). Collectively, these results suggest strong divergent selection across an island archipelago results in genomic changes in a suite of traits associated with climate adaptation over small spatial scales. Future research should move beyond studying univariate traits to better understand multidimensional responses to complex environmental conditions.
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Affiliation(s)
- Maybellene P Gamboa
- Department of Organismal Biology and Ecology, Colorado College, Colorado Springs, Colorado, USA
| | - Cameron K Ghalambor
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA.,Department of Biology, Centre for Biodiversity Dynamics (CBD), Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - T Scott Sillett
- Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| | | | - W Chris Funk
- Department of Biology, Graduate Degree Program in Ecology, Colorado State University, Fort Collins, Colorado, USA
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